Tobacco



United States Patent 3,3i3,3il7 TOBACCO Wilmer A. Rohde, Winston-Salem, N.C., assignor to R. J. Reynolds Tobacco Company, Winston-Salem, N.C., a corporation of New Jersey No Drawing. Filed Apr. 13, 1965, Ser. No. 447,914

a 14 Claims. (Cl. 13117) This application is a continuation-in-part of my copending application, Ser. No. 352,371, filed Mar. 16, 1964, now abandoned.

This invention relates to tobacco and has for an object the provision of a tobacco composition having improved aroma and flavor.

It is well known in the tobacco art that the domestic tobaccos which are exemplified by burley, Maryland, fluecured, bright leaf or Virginia tobaccos are low in flavor as compared with so-called oriental or aromatic tobaccos which are imported from Turkey, Greece, Bulgaria, Yugo slavia, Rhodesia and Russia. Accordingly, it has been common practice in the tobacco industry to prepare blends of domestic and oriental tobaccos in order to provide cigarettes which have desired flavor and aroma characteristics. Accordingly, it is an object of this invention to provide a domestic tobacco which has an enhanced flavor and aroma.

An additional object of this invention is to provide a smoking tobacco or product which has been treated in such manner as to impart an aroma or flavor considered pleasing to the smoker.

An additional object of the invention is the provision of smoking products such as cigarettes, cigars or pipe tobacco having enhanced flavor and aroma characteristics.

In accordance with one embodiment of this invention a tobacco product is provided to which has been added a small amount of a compound having the following for mula:

wherein R is selected from the group consisting of alkyl and cycloalkyl groups of 1 to 8 carbon atoms and R R R and R are selected from the group consisting of hydrogen and alkyl groups of 1 to 4 carbon atoms.

The preparation and description of various specific representative tobacco additives of the present invention are as follows: (All temperatures are in degrees Centigrade) 4-KETO-NONANOIC ACID The 4-keto-nonanoic acid can be synthesized directly by the addition of a Grignard reagent to succinic anhydride. A detailed description of the synthesis of the tobacco additive is as follows:

A 3-liter flask equipped with stirrer, reflux-condenser and a pressure equalizing addition funnel was charged with 100 grams (1 mole) of finely pulverized, vacuum dried succinic anhydride and 400 milliliters of anhydrous ether. A Grignard reagent prepared from 24.3 grams (1 mole) of magnesium and 151 grams of l-brornopentane in 300 milliliters of anhydrous ether was placed in the addition funnel and the system kept under dry nitrogen. The Grignard reagent was added dropwise to the stirred solution of succinic anhydride at such a rate as to keep the ether below reflux reflux temperature. The addition was complete in 5 hours, after which the reaction mixture was hydrolyzed with 500 milliliters of hydrochloric acid. The water layer was separated from the ethereal organic layer and extracted with three SOD-milliliter portions of 'ice ether'and the combined ether solution was dried over sodium sulfate. Upon concentration of the ether layer, by distillation over a steam bath to 400 milliliter volume, a considerable amount of white solids precipitated from solution. This precipitate was removed by filtration to furnish 21.3 grams of succinic acid, melting point 186.

Complete removal of ether from the filtrate was done in vacuo to leave a residue of 108.4 grams of a light yellow oil. A benzene solution of this oil furnished another 7.5 grams of succinic acid. The filtrate was again concentrated and chromatographed on a 7.5 centimeter column containing 1 kilogram of silicic acid made up as a hexane slurry. Elution with etherh-exane furnished 38.3 grams of the di-addition product, 4-hydroxy- 4-pentyl-nonanoic acid y-lactone; 4.3 grams of an unidentified alcohol was next eluted with of ether-hexane. Elution was ether-hexane furnished 36.5 grams of the desired 4-lceto-nonanoic acid, melting point approximately 67-68".

4-OXO-5-METHYLOCTANOIC ACID CH; O

This compound was prepared via the Grignard reaction of 2-bromopentane (151 grams) and succinic anhydride (100 grams). Work-up of the Grignard reaction yielded 91 grams of oil that was dissolved in 1 liter of etherexane and adsorbed on a 7.5 centimeter column holding 1 kilogram of silicic acid, made up in a hexane slurry. Elution was 25-35% ether-hexane furnished 22.5 grams of the title compound whose structure was confirmed by its nuclear magnetic resonance spectrum.

This compound is reported in the literature as having a boiling point of 1305-1307 at 21 millimeters mercury pressure.

3-CYCLOPENTANOYLPROPIONIC ACID This 'y-keto acid was also prepared by a Grignard reaction. The Grignard reagent, prepared from 75 grams (0.5 mole) of cyclopentyl bromide and 12.2 grams of magnesium in 300 milliliters of dry ether, was added to grams (0.5 mole) of succinic an'hydride suspended in 500 milliliters of dry ether at room temperature under nitrogen atmosphere. After hydrolysis of the reaction mixture and separation of the other layer, the water layer was extracted with three ZOO-milliliter portions of methylene chloride. The ether and methylene chloride solutions were combined and dried. Upon partial concentration of the organic material, 4 grams of succinic anhydride were filtered oil, and 61 grams of residue remained after complete removal of solvent. This residue was refluxed with 200 milliliters of -90 ligroin, and the hot ligroin was then decanted from the insoluble oil. Concentration of the ligroin solution furnished 1.5 grams of fine white crystals, melting point -76". The infrared spectrum with bands at 5.87, 7.03, 7.20, 7.45, 7.75, 7.97, 8.15 and 10.70 (broad, strong) a; and the nuclear magnetic resonance spectrum, 7:7.30 (5) triplet 8.34 (8) saturated 'CH and the mass spectrum, with a parent peak of mass 170, confirmed the structure of the title compound. Chromatography of the oil residue from the refluxing ligroin solution furnished another 9 grams of pure 3-cyclopentanoyl propionic acid, melting point 7576, after recrystallization from 60-90 ligroin.

4-OXODECANOIC ACID ll C6H1i 'C-"CH2CI'I2COOH (:1) Preparation of amyl flnyl carbinol A Grignard reagent was prepared from 151 grams of l-bromopentane added dropwise over a two-hour period to 24 grams of magnesium in 300 milliliters of anhydrous ether, held at ice bath temperature, in a flask equipped with a reflux condenser, drying tube, addition funnel, and stirrer kept under a dry nitrogen atmosphere. To this Grignard was added 96 grams of Z-furaldehyde diluted with 250 milliliters of ether. The addition was done at such a rate as to just allow a gentle refluxing of the ether. The solution was stirred for one hour after the addition of furfural was completed, after which it was hydrolyzed with a saturated solution of ammonium chloride. The ether layer was separated, dried and the solvent removed under aspirator pressure. The residue, transferred to a 500 milliliter flask, was distilled at reduced pressure through a 30 centimeter Vigreux column. After a forerun of furfural (collected at 30 at 1 millimeter mercury pressure)-. ll7 grams of the amyl furyl carbinol, boiling point 78 fit l millimeter mercury pressure, were collected (70% yield).

(b) Ring cleavage of nmyl fznyl carbz'nol To 115 grams of the amyl furyl carbinol, in a 500 milliliter flask equipped with reflux condenser and drying tube, were added 400 milliliters of a solution of 1.6 grams of hydrogen chloride in absolute ethanol. The mixture was heated on the steam bath for three hours under reflux, after which approximately 250 milliliters of ethanol were removed under aspirator pressure. The residue was treated with solid sodium carbonate to neutralize the hydrogen chloride and distilled at 3 millimeters of mercury. After a forerun of 20 grams was collected up to 100, which was a mixture of furfural and ketoester, 77 grams of ethyl 4-oxodecanoate was collected, boiling point 100- 116 at 3 millimeters mercury pressure, a 36% yield. Hydrolysis of a methanol solution of the ester in the usual manner with potassium hydroxide furnished the 4-oxodecanoic acid in 98% yield, melting point 70-72, after recrystallization from 6090 ligroin.

4-OXOOCTANOIC ACID CilIe( i CH'r-CH2C-OOII A Grignard reagent Was prepared from 123 grams (1 mole) of propyl bromide and 24.3 grams (1 mole) of magnesium to which 96 grams of furfural were added. Careful addition of the ammonium chloride solution, for hydrolysis of the reaction, produced a solid granular mass from which the nearly dry ethereal solution of the reaction product was decanted. lowed by distillation of the crude residue (113 grams), yielding 117 grams (83.6% yield) of propyl furyl carbinol, boiling point 56 at 1 millimeter mercury pressure (7 grams of unreacted furfural was collected in the forerun).

The 117 grams of propyl furyl carbinol were refluxed with 400 milliliters of absolute ethanol containing 1.6 grams of hydrogen chloride for 3 hours, as was previously done. This time the ethyl ester was not isolated from the ring cleavage reaction, but the ester was hydrolyzed directly by adding 50 grams of potassium hydroxide in 200 milliliters of water to the reaction solution. After two hours (the mixture was not heated) the reaction solution became very black and considerable tarry material separated out. This alkaline solution was then diluted with 300 milliliters of water and extracted with ether. The clear, dark brown, aqueous layer was treated with charcoal, filtered through a Celite bed, and acidified with dilute (3: 1) sulfuric acid. The brown oil which separated was extracted from the water with ether, and the ethereal Removal of the ether, folobtained. The compound was found to have a melting point of 45-47 C.

4-OXOHEXANOIC ACID This compound was prepared ina 0.5 molerun using a commercial methyl magnesium bromide. Due to charring during the rin opening of the methyl furyl carbinol, the cthyl-4-oxohexanoate was isolated. After removal by filtration of some 13.7 grams of charred material, the residue was distilled at 2 millimeters pressure and the fraction collected at boiling point 75 to furnish 23.5 grams of ethyl-4-oxohexanoate. Hydrolysis of the ester provided 4-oxohexanoic acid, melting point 39-40".

The additive compounds when employed in tobacco products in accordance with the invention, impart flavor and aroma, particularly during smoking, which many smokers consider to be desirable in tobacco products. However, it is pointed out that methods for defining or characterizing the quality of a flavor or aroma in the tobacco art are almost purely subjective and different smokers may define the same flavor quite diflerently. Thus, the compound 4-keto-nonanoio acid has been described by some as imparting an earthy mushroom-like aroma, while the 4 keto-decanoic acid produces a more delicate or light mushroom-like note. Also, compounds included within the broad scope of this invention where the alkyl substituents in the generic formula are somewhat diflerent may impart flavor and aroma to the tobacco products which may be somewhat different or difiicult to characterize on the basis of any recognized standard. Thus, a camphoraceous note has been detected with 4-oxo-5-methyloctanoic acid and 3-cyclopentanoyl propionic acid. Thus, the compounds comprehended by this invention by subjective tests impart characteristic flavors which are desirable in tobacco products and the smoke therefrom even though the exact character thereorraay. not be describable on the basis of known standazei In accordance with this invention a compound ethbraced by the generic formula given above is added to tobacco or applied to a smoking article or its component parts in amounts ranging from about 0.0005 to about 0.5 by weight of the product. Preferably the amount of the additive is between about 0.001 and 0.02%. The exact amount to use will depend upon the amount of flavor and aroma desired and the particular compound or mixture thereof that is used. The additives may be incorporated at any step in the treatment of tobacco but are preferably added after aging, curing and shredding and before the tobacco is formed into cigarettes. Likewise, it will be apparent that only a portion of the tobacco need be treated and the thus treated tobacco may be blended with other tobacco before the cigarettes or other smoking articles are formed. In such case the tobacco treated may have the additive in excess of the amounts indicated so that when blended with other tobaccos the final product will have the percentage within the indicated range.

It will be particularly apparent that the manner in which the additives are applied to the tobacco is not particularly/important since it may be done in the form of spraying or dipping, utilizing suitable suspensions or solutions of the additive. Thus water or volatile organic solvents, such as alcohol, ether, acetone, volatile hydrocarbons and the like, may be used as the carrying medium for the additives while they are being applied to the tobacco. Also, other flavor and aroma producing additives, such as those disclosed in Jones United States Patent No. 2,766,145 and Schumacher United States Patent No. 2,978,365, may be incorporated into the tobacco with the additives of this invention.

In accordance with one specific example of this invention, an aged, cured and shredded burley tobacco is sprayed with a 1% ethyl alcohol solution of the 4-keto-nonanoic acid in an amount to provide a tobacco composition containing 0.01% by weight of the additive on a dry basis. Thereafter, the alcohol is removed by evaporation and the tobacco is manufactured into cigarettes by the usual techniques. The cigarette, when treated as indicated, has a desired and pleasing aroma which is described by some as mushroom-like, and which is particularly detectable and pleasing in the main and side smoke streams when the cigarette is smoked.

While this invention is particularly useful in the manufacture of cigarette tobacco, it is also suitable for use in connection with the manufacture of pipe tobacco, cigars, and other tobacco products formed from sheeted tobacco dust or fines which are well known to the art. Likewise, the additives of the invention, being appreciably volatile, can be incorporated with materials such as seam paste and the like which are used along with tobacco to form a product adapted for smoking. Furthermore, the additive compounds may be added to certain tobacco substitutes of natural or synthetic origin and by the term tobacco as used throughout this specification is meant any composition intended for human consumption by smoking or otherwise, whether composed of tobacco plant parts or substitute materials or both.

Those modifications and equivalents which fall within the spirit of the invention and the scope of the appended claims are to be considered part of the invention.

1 claim:

1. A domestic tobacco having added thereto a small amount sulficient to alter the flavor of the tobacco of a compound having the following formula:

R2 R4 Ri CC-OCOOH it. it. wherein R is selected from the group consisting of alkyl and cycloalkyl groups of 1 to 8 carbon atoms and R R R and R are selected from the group consisting of hydrogen and alkyl groups of 1 to 4 carbon atoms.

2. A domestic smoking tobacco having added thereto between about 0.0005 and about 0.5% by weight of a compound defined in claim 1.

3. A tobacco product having added thereto a small amount sutficient to improve the flavor of the tobacco product of a compound defined in claim 1.

4. A product adapted for smoking having added thereto a small amount suflicient to improve the flavor of the tobacco product of a compound defined in claim 1.

5. A tobacco product having added thereto between about 0.0005 and about 0.5% by weight of a compound defined in claim 1.

6. A tobacco product having added thereto between about 0.001 and about 0.02% by weight of a compound defined in claim 1.

7. A product adapted for smoking having added thereto between about 0.0005 and about 0.5% by weight of a compound defined in claim 1.

8. A product adapted for smoking having added thereto between about 0.001 and about 0.02% by weight of a compound defined in claim 1.

9. A process of improving tobacco which comprises adding thereto a small amount sufiicient to improve the flavor of the tobacco of a compound having the following formula:

Ih-C-C-G-COOH 1 13 1 45 wherein R is selected from the group consisting of alkyl and cycloalkyl groups of l to 8 carbon atoms and R R R and R are selected from the group consisting of hydrogen and alkyl groups of 1 to 4 carbon atoms.

10. A process of improving the flavor of smoking tobacco which comprises adding thereto between about 0.0005 and about 0.5 by Weight of a compound defined in claim 9.

11. The process recited in claim 10 wherein the stated percent is between about 0.001 and about 0.02%.

12. A process of improving a tobacco product which comprises adding thereto a small amount sufiicient to improve the flavor of the tobacco product of a compound defined in claim 9.

13. The process recited in claim 12 in which the small amount of the additive is between about 0.0005 and about 0.5% by weight.

14. A tobacco product having added thereto a small amount sufficient to alter the flavor of the tobacco of a compound having the following formula:

wherein R is selected from the group consisting of alkyl and cycloalkyl groups of 1 to 8 carbon atoms and R R R and R are selected from the group consisting of hydrogen and alkyl groups of 1 to 4 carbon atoms.

No references cited.

SAMUEL KOREN, Primary Examiner. M. D. REIN, Assistant Examiner. 

1. A DOMESTIC TOBACCO HAVING ADDED THERETO A SMALL AMOUNT SUFFICIENT TO ALTER THE FLAVOR OF THE TOBACCO OF A COMPOUND HAVING THE FOLLOWING FORMULA: R1-CO-C(-R2)(-R3)-C(-R4)(-R5)-COOH WHEREIN R1 IS SELECTED FROM THE GROUP CONSISTING OF ALKYL AND CYCLOALKYL GROUPS OF 1 TO 8 CARBON ATOMS AND R2, R3, R4 AND R5 ARE SELECTED FROM THE GROUP CONSISTING OF HYROGEN AND ALKYL GROUPS OF 1 TO 4 CARBON ATOMS. 